Coaxial line seal



5, 1946- E. MOUROMTSEFF ET AL 2,394,398

COAXIAL LINE SEAL INVENTORS 1. 3 MOUEO/V76'EFF' G. M /A A /C'/t' ATTORNEY Filed March 20, 1942 Patented Feb. 5, 1946 COAXIAL LINE SEAL Ilia E. Monromtsefl, Montclair, and George M.

Dinnick, Bloomfield, N. 1., assignors to Westinghouse Electric Corporation. East Pittsburgh, Pa a corporation of Pennsylvania Application March 20, 1942, Serial No. 435,504

' 5 Claims. (Cl. 174-19) This application is, as to basic subject matter, a division of our co-pending application Serial No. 360,867, filed October 9, 1940, for Ultra-high frequency oscillator," now issued as Patent No. 2,288,895 under date of May 19, 1942. The invention of the present application is directed particularly to the concentric or coaxial line construction utilized in transmitting the wave energy. Both the broad concept of said co-pending application and an improved species are here shown.

.An object of the present invention is to provide a transmission line presenting minimum obstacle to free passage of the wave energy.

Another object of the invention is to obtain adequate sealing of the tubular and rod portions of the coaxial line away from the ends of both said portions.

A further object of the invention is to enable a coaxial line to be vacuum sealed and at the same time permit attachment of the loop end of the rod to the extreme end of the tube.

Yet another obiect of the invention is to insure maximum conductivity of the tube combined with physical strengthening of the tube and seal.

Again. an object of the invention is to provide a seal controlled in expansion such that the tube and glass seal have substantially the same coefilcient at the re ion of the seal but with a good conductor passin the seal to the end of the tube.

Still further objects of the invention will appear to those skilled in the art as the description progresses. both by direct statement thereof and by implication from the context.

Referring to the accompanying drawing in which like numerals of reference indicate similar parts throughout the several views:

Figure l is a sectional view of a concentric or coaxial line output from a resonator embodying our invention:

Figured 2 is a cross section thereof on line II-II; an

Figure 8 is a partial section from the said copending application showing the broad concept of the invention.

In the specific embodiment of the invention illustrated in said drawing, the reference numeral ll designates the tubular portion, preferably of copper or other good electrical conductor, of a transmission line which may be part of or projects from a source of wave generation. such as from the metallic shell H of a hollow-body resonator forming part of a high frequency wave generator of the character shown in our said co-pending application. Extending coaxially within tube It is arodorcenterconductcriihavinganinnerloop II in the resonator and an outer loop it constituting an output coupling and shown entirely outside of the tube in the open atmosphere. The inner loop and inner portion of the rod I! are subject to the vacuum of the resonator, and a seal it is accordingly made between the rod and tube wall to maintain the vacuum.

As shown. the seal it is constituted by a plug of glass which is within the outer end of th tube so the end edge of the said tube will be exposed and unobstructed by any sealing means. The end of the output loop it may therefore be secured, as by soldering. welding, orotherwise, to the extreme end of the tube. Attachment-to the extreme end of the tube is important, since the current hows on the inside surface of the tube. This gives opportunity of making connection without any sudden changes in the fiow or no doubling back in the flow path to pass to the loop.

The above description applies to all figures of the drawing. Refen'ing now to Figures 1 and 2 more specifically it is to be observed that the outer end of the coaxial line tube It which is the part thereof containing the sealing plug II, is const ucted in two parts. There is an outer part or collar it the coeillclent of expansion whereof referably approximates that of the plug. Blight tendency of greater expansion of the plug than of the collar is preferred. so any tension set up will be compressive at the joint. The material of which said collar is formed is preferably of greater strength than the copper portion of the tube. and may well be an alloy of composition essentially of nickel. cobalt and iron sold under the trade name of "Kovar" and the plug is preferably of borosilicate glass. details of both of which are given in Patent 2.062.335 toBcott. of December 1, 1936.

The conductivity of "Kovar" is very ccnsiderably less than copper. A feature of the present invention resides in the use of Kovar for its strength and desirable coemcient of expansion. and at the same time in obtaining the benefit of conductivity of copper. Accordin ly the tube is formed to provide a part constituting a thin. cylindrical inner skin or sleeve ll of copper within the collar It upon the inside surface thereof. This copper sleeve part of the tube may be an integral continuation of the more rugged body of the tube but of reduced thickness, or may be plated or otherwise formed in place. It is characterised by its thinness of wall thickness and its good electrical conductivity together with ductility or flexibllity such that it will follow the expansion and contraction of the surfaces with which it is engaged or attached. Said sleeve is interposed bethe Kovar collar and the plug and, extending from the main body of tube I! to the outer end of the collar, forms an electrical conductive path along the inside oi the collar to the loop at the outer end thereof. While we specifically refer to a loop as a part of the conductive means at the end of the Kovar" collar and beyond the plug, it is to be understood other transmission means than that may be employed if found preferable.

The construction and beneficial results obtained by the disclosure of Figures 1 and 2 are characterized by the security of seal of the tube by its controlled expansion and contraction substantially equal to that of the plug, by the strengthening presence of the "Kovar" collar, and by the advantageous high order of conductivity of the copper tube and its extension or sleeve throughout the length of the tube and to the outer end thereof. Furthermore the inventive concept includes the provision of a seal within the tube by which it becomes now practical to attach the loop at the physical end of the tube and thereby avoid any doubling back of the flow path to pass to the loop.

Since the various details of construction as well as the precise relation and functioning of parts are subject to variation and change without departing from the inventive concept or scope of the invention, it is intended that all matter contained in the specification or illustrated in the drawing, shall be interpreted as exemplary and not in a limiting sense. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein shown and described and all statements of the scope of the invention herein set forth as a matter of language which might be said to fall therebetween.

We claim:

1. A coaxial line seal comprising a conductive tubular portion, a conductive rod extending therethrough, a reenforcing collar around a part of the tubular portion, and an insulative plug within the part of the tube surrounded by the collar, said plug being sealed to both the tubular portion and to the rod.

2. A coaxial line seal comprising a conductive tubular portion. a conductive rod extending therethrough, said rod being looped at its outer end and secured to the end of the said tubular portion, and an insulative plug situated within said tubular portion clear of said end thereof and sealed to both the inside surface of the tubular portion and to said rod.

3. A coaxial line seal comprising a tubular portion of highly conductive material of the character of copper and having embedded as a part thereof a collar of material stronger than copper and characterized by a diflerent coeflicient of expansion, a rod conductor extending through the tubular portion, and a plug within the collar sealing the passage therethrough around the rod conductor, said plug being situated within said collar and having substantially the same coeflicient of expansion.

4. A coaxial line seal comprising a tubular portion of highly conductive material of the character of copper and having embedded as a part thereof a collar of material less conductive electrically and physically stronger than said conductive material of the tubular portion, said conductive material of the tubular portion being continuous from end to end of said tubular portion and projecting beyond one end of the said collar, and a sealing plug for the passage through said tubular portion, said plug being within the confines of said collar.

5. A coaxial line seal comprising a tubular portion of highly conductive material of the character of copper and characterized by ductility, said tubular portion having a part thereof reduced in thickness and comprising a thin wall sleeve, a plug in the sleeve passage of said tubular portion sealed to the said thin wall of the sleeve, and a collar of different material around said sleeve having substantially the same coefilcient of expansion as the plug, said sleeve thereby having an annular part thereof between said collar and plug and by virtue of its thinness and ductility responding to the expansion and contraction of said collar and plug and maintaining a tight seal with the plug.

ILIA E. MOUROMTSEFF. GEORGE M. DDINICK.

Disclaimer 2,394,398.-llz'a E. M ouromtsefi, Montclair, and George M. Dz'nm'clc, Bloomfield, N. J. COAXIAL LINE SEAL. Patent dated Feb. 5, 1946. Disclaimer filed Jan. 31, 1951, by the assignee, Westinghouse Electric Corporation. Hereby enters this disclaimer to claim 1 in said specification.

[Oyfieial Gazette February 27, 1951.]

Disclaimer 2,394,398.Ilia E. M ouromtsefi', Montclair, and George M. Dirmz'clc, Bloomfield, N. J. COAXIAL LINE SEAL. Patent dated Feb. 5, 19%. Disclaimer filed Jan. 31, 1951, by the assignee, Westinghouse Electric Corporation. Hereby enters this disclaimer to claim 1 in said. specification.

[Ofiicz'al Gazette February 27, 1.951.] 

